Temperature is symbolic of mood and the escalation or decreasing of emotional intensity. Hot weather is synonymous with hot tempers and the prevalence of passion.
The desire to cool the air by artificial means is symbolic of your ability to regulate such elements of life at your own whim.
The larger the air-conditioning unit, the greater the sense of control that is being expressed. In this way, a window unit is reflecting a modicum of control, whereas central air relates to a more comprehensive desire to rein in your passions.
If the air conditioning is broken, such a dream relates to the inability to keep cool under pressure.
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